This request is for RCDA salary support for research experience and training in male sexual behavior and dysfunction. The broad longterm objective of this work is to elucidate mechanisms controlling erection, emission, and ejaculation and to develop treatments for dysfunction. The specific aims are to 1.) determine effects of compounds of four broad classes of neuropharmacologicals on specific components of sexual behavior, particularly erection, emission, and ejaculation function in horses; 2.)develop techniques for enhancing or inducing erection, emission, and ejaculation; 3.) elucidate mechanisms of control of the various components of sexual behavior. These agents will be studied in the domestic horse stallion, an animal with genital anatomy, copulatory pattern, and sexual dysfunction remarkably similar to that of humans. Effects of agents on sexual behavior will be evaluated before, during, and after treatment, in A-B-A and Latin square designs. Behavioral response reflecting specific components of sexual behavior (libido, erection, emission, or ejaculation) will be measured in heterosexual behavior tests. Erection, emission, and ejaculation will also be evaluated during spontaneous erection and masturbation, which is a regularly occurring, easily observable behavior of horses somewhat similar to NPT in humans. Effects will be studied both in normal animals and stallions with sexual behavior dysfunction. RCDA salary support will facilitate the candidate's completion of current clini- cal trials and preliminary experiments in pharmacological manipulation sexual behavior, followed by a program of research training and experience focused in that area.